Sound and picture reproducing apparatus



Sept. 13, 1938. R. PLATT-HEPWORTH 2,130,010

SOUND AND PICTURE REPRODUCING APPARATUS Filed 1955 UNITED STATES PATENT OFFICE SOUND AND PICTURE REPRODUCING APPARATUS Robert Platt-Hepworth, Padding ton, near Sydney, Australia I Application August 15, 1935, Serial No. 36,442 In Australia August 30, 1934 '4 Claims. (01. Bil-16.2)

This invention relates to a combined sound the independent driving of these several mechaand motion picture projector, designed with a nisms is the dominant feature of the invention, view to securing compactness, simplicity, and to which its other features are subordinate or high mechanical efficiency, particularly as a reaccessory. Therefore, in the practical expression suit of the novel gearing train principle emof my principle I do not limit myself to the one 5 ployed. It will be seen that the design makes epresented by the drawing, as the whole object possible a light shutter system occupying subof my invention is to bring about effective isolastantially the whole of the side area of the protion of the several film transporting zones from jec'tor. This arrangement results in efiiclent one another.

lo light interruption because of the large shutter, My arrangement permits the use of a shutter and efiective heat dissipation due to the area of oi sufiicient diameter to cover the full side area the shutter as well as to the fact that the shutof the projector casing; such a shutter by reason system is disposed between the radiant source of its diameter ensures a clear cut-oh of light and the film. The shutter system is unobtrusive at large and full aperture and a full area light it and is so disposed as to render injury to the op" beam and good cooling. A fly vane steadying lo orator unlikely. fan is fitted optionally on the overhung end oi in a machine embodying the present inven= the primary shaft, and is utilized to create an tion he primary or power shaft is located sub air blast for maintaining a cool condition about stantiaiiy in the centre of the housing or frame. the lamp house and the condenser cell through to Around this central drive shaft, and meshing which the light beam passes to a reflector or a so with a pinion on it are grouped the several gears prism and thence to the picture gate. required for operation of the members eifecting The lamp house is supported on a pivot base the propulsion of the film throughout its path. and may be swung round thereon to direct the The gearing arrangement allows of effective aclight beam. towards the screen thus to enable it so commodation oi the light tube for the passage of to be used for lantern slide projection. so

the beam from its source to an orientation mir- In the accompanying drawing ror or reflector by which the beam is deflected Fig. l is a side elevation oi the projector; so that it strikes the picture gate. Thence it Fig. 2 is an interior plan view of the projector; passes to the objective and on to the screen. and

git These high speed assemblies, which may be 3 is a fragmentary section through the to belt or direct motor driven, possess a high degree casing, showing the recessed casing and drive to oi momentum or inertia due to the flywheel and the take up spool. shutter system weight. Another advantage is it is a housing of narrow box section with that because of the high speed of the fly wheel bearing holes formed in its sides for the spindles as relatively to the sprocket shaft speed, a much which carry gears and sprockets. it is the pri smaller and lighter fly wheel can be used than mory drive spindle; it is extended through t e would be necessary if the fly wheel ran at sproclzrear side of the housing at It and carries a ct speed, in the conventional way. The several p ll y fly Whe l l5 5 and the rotor of an air sprocket gears are driven by the pinion or the blower it on the overhanging end 01' it. An elec speed assembly; these gears are staggered Eric motor may be direct coupled to this spindle so with the object of providing each gear with its 1 it y e t drill/en, tho S r d ameter own working face on the pinion. groove (55) carrying the belt for sound speed Since there is no connection existing between drive and the larger diameter groove (it) carthese sprocket gears except through the high rying the belt for silent speed drive. l5--i6 may speed driving shaft and pinion, any disturbances be grooved pulleys, in which case a separate fly it or torque irregularities emanating from the fiucwheel is fitted. tuating zones such as the picture or intermittent A primary drive pinion H, which is fixed on zone, and feed and take-up zones, must upset the spindle it drives three toothed wheels (H, or disturb the momentum of the high speed as- 20 and 34) which are grouped around it thereby so sembiy before any such disturbance can react unopposing the cross-wise thrusts and ensuring favourably to the sound or constant speed zone. steadiness. The wheel l1 and a sprocket it are The mechanism of the sound zone is therefore both keyed to a spindle l9. The wheel it drives practically isolated from the influences tending the intermittent sprocket 23 through the com to disturb its regularity. Zonal isolation of the shaft pinion 2| (which carries a fly wheel 21).

' 5y, mechanism oi the several film driving zones, and The intermittent gear is preferably a "Geneva cross" device which is a common element in picture projectors. A transfer gear wheel 24 which is fixed on the side of the wheel 28 drives the wheel 25 which is fixed on the spindle of the film take-up sprocket 28. 28 is a pulley which drives the take-up film spool (not shown) through a belt 88.

The safety shutter 32 and the cut-oi! shutter II are both carried on the overhung end of the spindle l2 between the fly wheel l5l8 and the rear side of the housing l8. These shutters cover the full height of the housing (see dotted circle in Fig. 1) and because of their large area and high peripheral speed and large area apertures they ensure clean and quick opening and cutting of the light beam from the lamp house 5| and rapidly radiate heat absorbed from the lamp rays. The lamp house is carried on a pivot base on a bracket and may be swung round on this base to direct the lamp rays through the condenser cell 52 to the prism or flat reflector by which they are diverted forwardly through the picture gate 45. To provide for the shutters being disposed closely behind the rear wall of the housing that wall is set back as shown in Fig. 3 to form a pocket 88 to accommodate the pulley 28.

The third drive from the primary pinion II is applied through the wheel 84 to a gear wheel 85 on the spindle 81 which carries the sound sprocket 88 and a fly wheel 88.

The sound assembly includes an exciter lamp behind the optical tube 88 and a cylindrical box containing the photo-electric cell 4|. 40 is the film sound gate box.

The film 58 entering over the guide roller 42 passes round the film feed sprocket is on which it is held meshed by an idler roller 48 and thence goes over a free guide roller 48 and curves forwardly and downwardly in an erect loop to its entry through the top of the picture gate 45. The film emerges at the bottom of the gate 45 and passes under the framing roller I54 to the intermittent sprocket 28 on which it is held in mesh by a shoe or roller 48 and thence in a pendent loop goes up over a smooth face roller 46 which is fixed on the spindle 22 of the wheel 20, being frictionally influenced thereon by the idle rollers 84-48, and thence over the cylindrical face of the photo-electric cell box 48. As it passes over the light slit in the side of the box 48 it controls the passage of light rays from the optical exciter system 88 to the photo-electric cell. From this point it goes round a segment of the sprocket 88 on which it is held meshed by idler 48 and then passes in a pendent loop to the take-up sprocket 28 on which it is held meshed by the idler 48. From the sprocket 28 it goes over the guide roller 58 to the take-up spool (not shown) below.

The diameter of the roller 48 is determined so that its peripheral speed will be slightly less than the delivery speed of the sprockets in order that it willconstrain the film reversely and assist in holding it tensioned as it approaches the sound gate. An additional impedance device may be fitted to provide appropriate tension on the film during its course to and over the sound gate. This impedance device is a shoe 5| carried on a flexible adjustable arm SI and bearing down on the fllm margins. To prevent risk of scratching the film two thin steel strips are fixed externally to the box 48 spaced apart to form supports for the film margins thus to hold the film face a few thousandths of an inch clear from the box surface. The impedance shoe 5| bears on the fllm where it is supported by these strips, and operates to hold the film tensioned against the pull of the sprocket 86 ensuring flatness in its passage over the sound gate.

The condenser tube 52 through which light rays pass from the lamp house II (in alignment with it) is sufliciently above the spindle ii to allow clearance for the lamp house to be swung round to direct the light rays forward when it is required to utilize the machine for projection with lantern slides.

The wheels are toothed spirally and the angles are chosen so that a side thrust is applied to the fly wheel 38 influencing it towards the housing side and thus imposing frictional resistance proportional to the reaction of the drive, whereby steadiness of drive is obtained as the frictional resistance rises when'speed of drive is increased.

The whole of the gearing is enclosed in the housing Ill, and the film and its sprocket and roller assembly and the gates are protected in the near side by casing 84. The load on the primary drive pinion ii is cross balanced by the grouping of the driven wheels around it, and a compact arrangement of the gearing in which the gears are disposed in staggered arrangement permitting of a separate tooth face for each gear plane within the housing, and enabling reduction of the overall dimensions of the machine very substantially. Access to the gearing assembly is obtainable by drawing the rear side cover off the housing without interfering with any part of the equipment which is contained in the film assembly casing on the near side of the machine.

What I claim as my invention and desire to secure by Letters Patent is:-

1. A motion picture projector including a sound unit, a primary drive shaft, a housing receiving said shaft centrally thereof, a fly wheel, cut-off shutter and pinion carried by said drive shaft, three gear wheels disposed about said pinion and in mesh therewith, a continuous film feed sprocket driven by the first of the three gear wheels, a sound wheel sprocket driven by the second gear wheel, an intermittent sprocket and a take-up sprocket, said intermittent sprocket and take-up sprocket being driven by the third gear wheel and said sprockets being located laterally of the plane of the drive shaft spindle.

2. A motion picture projector as claimed in claim 1, in which the cut-oil shutter covers substantially the full dimensions of the housing side, the picture projector lamp house being located on the same side of the housing and spaced therefrom, and a pulley adapted to provide driving means for taking up the film inset in a pocket in the housing to provide clearance for the shutter rotation.

3. A motion picture projector as claimed in claim 1, in which a film tensioning drum is associated with the housing and driven by one of said gears at a peripheral speed different from that at which the film driving sprockets are driven.

4. A motion picture projector according to claim 1 wherein the gear wheels meshing with the drive pinion on the primary shaft are provided with spiral teeth, with the angular teeth disposed in relation to the direction of drive so as to influence a fly wheel axially towards frictional contact with the wall of the housing and thereby procure brake action proportional to the driving reaction.

ROBERT PLATT-HEPWORTH. 

